The grizzly bear – that 800-pound omnivorous tank of silver-tipped fur, four-inch foreclaws and sometimes-testy disposition – is classically thought of in the lower 48 states as a beast of western mountains: the king of Yellowstone and Glacier, dining on roots and marmots and huckleberries in high-country wilds. A couple of hundred years ago, however, the “griz” also counted the prairie rivers and badlands of the Great Plains as part of its dominion. Shot and harassed out of this open-country range, the great bear has lately shown some interest in reclaiming at least a little bit of its old grassland stomping grounds.
The Great Plains Grizzly
In the early 1800s, when Captains Meriwether Lewis and William Clark led their Corps of Discovery westward from St. Louis to explore possible water routes to the Pacific, the grizzly ranged far eastward on shortgrass and mixed-grass prairies of the Great Plains.
A comprehensive 2002 Conservation Biology analysis of the historical range of the grizzly in the lower 48 States suggested the bear likely occupied most of the Dakotas and the far western reaches of Nebraska, Kansas and Oklahoma as well as extreme West Texas. Rather than roaming widely over the sprawling plains, grizzlies likely mostly clung to the gallery forests and brushy thickets of prairie watercourses.
Sciencing Video Vault
Besides the lush greenery and abundant fruit in the river corridors, prairie grizzlies once had a mindboggling bounty in the huge bison herds of the Great Plains. Though grizzlies may have occasionally killed bison calves and injured adults, buffalo probably mainly served as bear food in the form of scavenged carcasses.
Revered by Plains Indians, the grizzly also impressed Lewis and Clark: Accustomed to the smaller, shier black bear of the East, they initially brushed aside native warnings about the "white bear's" ferocity, but that quickly changed once they’d experienced it for themselves firsthand. “A most tremendious looking animal,” Lewis wrote in May 1805, “and extreemly hard to kill.”
The Grizzly's Retreat
But kill the grizzly Euro-Americans did, plus generally drive it from its Great Plains homeland by turning the old buffalo steppes into grainfields and cattle ranches. By the 1920s, Ursus arctos horribilis in the American West was essentially confined to remote mountain ranges.
At the time of Lewis and Clark’s expedition, perhaps 50,000 grizzlies inhabited the lower 48. Today, the U.S. Fish and Wildlife Service estimates 1,400 to 1,700 grizzly bears call the conterminous U.S. home in five isolated populations: the Greater Yellowstone, the Northern Continental Divide, the Cabinet-Yaak, the Selkirk, and the North Cascades.
Montana’s New Prairie Grizzlies
For many decades, most of the Great Plains have been grizzly-less – though some silvertips fresh (and famished) from high-country hibernation along Montana’s Rocky Mountain Front have long trundled down to forage in the fertile prairie bottomlands of the Pine Butte Swamp. That 13,000-acre Nature Conservancy holding was almost a museum piece, preserving a prairie-griz tradition lost just about everywhere else.
Well, remarkably, nowadays it’s a tradition that appears to be having a revival. That’s especially so along and east of the Rocky Mountain Front, where Northern Continental Divide grizzlies – their population at least somewhat recovered thanks to federal protection – are again exploring former shortgrass digs on the Missouri Plateau (northernmost portion of the U.S. Great Plains).
Direct observations by ranchers and other residents as well as GPS tracking by biologists suggest grizzlies are likely traversing the open prairies via drainages such as the Teton, Marias, and Sun rivers, which provide both feeding grounds and shelter.
While a few of these bears have gotten themselves into trouble with farmers and ranchers, many go about mostly undetected by people: roaming under the cover of darkness and probably retiring during the day to aspen groves and riverside thickets.
One young male (or boar) grizzly followed the Teton River as far east as the Fort Benton area, within a stone’s throw of the Missouri River. Actually, this wayfaring bear navigated here twice: He was trapped near Loma in 2009 after killing a sheep and released in the Rockies west of Marias Pass, but the next year he’d returned to the plains – only to be caught again in the same vicinity after scarfing grain and raiding a chicken coop.
In June 2017, Montana Fish, Wildlife and Parks euthanized a pair of subadult male grizzlies near Stanford, east of the Missouri, after they killed a few calves. This was, as the agency noted in a press release, "the farthest grizzly bears have been east of the Rocky Mountain Front in more than a century."
Young male grizzlies such as these commonly roam widely as they seek out home ranges for themselves, and therefore it shouldn’t be terribly surprising to see them periodically rambling the prairie east of established Rocky Mountain Front grizzly populations. But it isn’t only males: Female grizzlies have been spotted on the plains as well, including a sow and three cubs in the fall of 2009 near Simms close to the Sun River, dozens of miles east of the mountains.
Denning on the Plains
Not only that, but a few enterprising grizzly sows have taken the next step in prairie recolonization by denning on the plains. Until very recently, most grizzlies recorded on the Montana prairies seemed to seasonally forage there and then return to the mountains to den for the winter. But in 2009, a female griz denned in the Deep Creek drainage south of Choteau, giving birth to a pair of cubs during her "off-season" lethargy. In 2012, a five-year-old sow overwintered on the Blackfeet Indian Reservation some 17 miles east of the Rockies and emerged the following spring with two youngsters of her own.
As a 2013 article in the Great Falls Tribune noted, these prairie lairs stood in stark contrast to the high-elevation dens grizzly bears typically excavate on north- or northeast-facing mountainsides, often under the roots of big subalpine trees. The Blackfeet Reservation den was situated on a shrubby but treeless hillside, while the Deep Creek sow burrowed out a 7.5-foot-long chamber in a gulch, lining the interior with pine boughs.
Female grizzlies in particular often den in the same region their mothers did, which suggests some of these prairie-born bears may seek their winter sleep in the lowlands, too.
Prairie Grizzly Menu
Grizzlies on the Montana plains no longer have a reliable larder of bison carcasses, but there’s no question this lightly developed, sparsely populated rangeland still has much to offer bears in the food department. The silvertips can seek out grasses, sedges, horsetail and other fresh springtime growth in the prairie river bottoms, the shrub tangles of which offer fruiting chokecherries, serviceberries, buffaloberries, hawthorns and elderberries in high summer and early autumn.
Grizzly Country, Reborn
It’s too soon to say what the future holds for grizzlies on the Great Plains. Though much of the North American steppelands east of the Rocky Mountains offer marginal bear habitat at best these days, regions such as Montana’s Missouri Plateau certainly have some lonesome corners a griz or two might be able to happily hole up in year-round.
The grizzlies that have appeared around Fort Benton and Stanford were not far west of the Missouri Breaks: a rugged swath of badlands, gulches and gallery forests along a remote reach of the Missouri River. Much of this rare expanse of Great Plains wilderness lies within the Charles M. Russell National Wildlife Refuge. “A bear could get lost out there and establish a home range and survive,” Mike Madel, a grizzly management specialist for Montana Fish, Wildlife and Parks, told New West in 2009.
And grizzlies north of the border in Alberta seem to be flexing prairie muscles, too, roaming eastward in the same Rocky Mountain Front/Great Plains ecological mosaic. One grizzly was collared nearly 200 miles east of the Rockies along the Milk River in south-central Alberta, having followed the drainage up from Montana.
Whether a self-sustaining grizzly population ever truly regains a foothold on the Plains or not, it seems clear a few grassland bears here and there are the new normal. Biologists and wildlife officials in both Alberta and Montana are urging property owners on the Rocky Mountain Front prairies to start treating their backyards as grizzly country. This means, among other things, securing garbage in bear-proof containers; installing electric fencing around chicken coops and orchards; and not leaving dog food, grain, livestock feed and other attractants lying around yards.